Evaluation of a Cryogenic Air Supply as a Breathable Air Source for a Confined Space

Details

• Personal Author:
  Carr J ; DeGennaro CR ; Lambie B ; Srednicki JR ; Yan L ; Yantek, David S. ; Yonkey JA
• Description:
  A breathable air source is required for confined space such as an underground refuge alternative (RA) when it is occupied. To minimize the risk of suffocating, federal regulation requires that mechanisms be provided and procedures be included so that, within the refuge alternative, the oxygen concentration is maintained at levels between 18.5% and 23% for 96 hours. The regulation also requires that, during use of the RA, the concentration of carbon dioxide should not exceed 1%, and the concentration of carbon monoxide should not exceed 25 ppm. The National Institute for Occupational Safety and Health (NIOSH) evaluated the cryogenic air supply's ability to provide breathable air for a refuge alternative. A propane smoker was used to simulate human breathing by burning propane gas which will consume O2 and generate CO2 and H2O. The rate of propane burned at the smoker was controlled to represent the O2 consumption rate for the breathing of a certain number of people. Two 96-hour tests were conducted in a sealed shipping container, which was used as a surrogate for a refuge alternative. While burning propane gas to simulate human oxygen consumption, cryogenic air was provided to the shipping container to determine if the cryogenic air supply will keep the O2 level above 18.5% and CO2 level below 1% inside the shipping container as required by the federal regulations pertaining to refuge alternatives. Both 96-hour tests simulated the breathing of 21 persons. The first test used the oxygen consumption rate (1.32 cu ft of pure oxygen per hour per person) specified in federal regulations, while the second test used the oxygen consumption rate specified by [1] (0.67 cu ft of pure oxygen per hour per person). The test data shows that during both 96-hour tests, the oxygen level was maintained within a 21%-23% range, and the CO2 level was maintained below 1% (0.2%-0.45%). The information in this paper could be useful when applying a cryogenic air supply as a breathable air source for an underground refuge alternative or other confined space. [Description provided by NIOSH]
• Subjects:
  Carbon Dioxide Carbon Monoxide Confined Spaces Mining Occupational Health Oxygen Respiratory System Safety
• Keywords:
  Author Keywords: Confined Space Breathable Air Breathing Carbon Dioxide Carbon Monoxide Confined Spaces Cryogenic Air Supply Gas Concentration Refuge Chambers Suffocation Underground Mining

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• Series:
  Mining Publications
• ISBN:
  9780791886717
• Publisher:
  The American Society of Mechanical Engineers
• Document Type:
  Text
• Genre:
  Proceedings
• Place as Subject:
  Ohio ; OSHA Region 3 ; OSHA Region 5 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PMRD - Pittsburgh Mining Research Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  9
• NIOSHTIC Number:
  nn:20067031
• Citation:
  Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition (IMECE 2022), October 30-November 3, 2022, Columbus, Ohio. Volume 9: Mechanics of Solids, Structures, and Fluids; Micro- and Nano-Systems Engineering and Packaging; Safety Engineering, Risk, and Reliability Analysis. New York: The American Society of Mechanical Engineers, paper no. V009T4A010, 2022 Oct; 9:V009T4A010
• Email:
  LYan1@cdc.gov
• CAS Registry Number:
  Carbon dioxide (CAS RN 124-38-9) ; Carbon monoxide (CAS RN 630-08-0) ; Oxygen (CAS RN 7782-44-7)
• Federal Fiscal Year:
  2023
• Peer Reviewed:
  False
• Source Full Name:
  Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition (IMECE 2022), October 30-November 3, 2022, Columbus, Ohio
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:03cec5e32d5029abcb1d50f1a3542a8bf44dc64345fcd0ba35953c9265708795c06b7fd9ff1c23bc76dcd812a547d64586d81ec9712f91993e9c83feaea6ab43
• Download URL:
  https://stacks.cdc.gov/view/cdc/215577/cdc_215577_DS1.pdf
• File Type:
  [PDF - 2.49 MB ]